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1.
Small ; : e2401656, 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-38994827

RESUMO

Electrochemical CO2 reduction is a promising technology for replacing fossil fuel feedstocks in the chemical industry but further improvements in catalyst selectivity need to be made. So far, only copper-based catalysts have shown efficient conversion of CO2 into the desired multi-carbon (C2+) products. This work explores Cu-based dilute alloys to systematically tune the energy landscape of CO2 electrolysis toward C2+ products. Selection of the dilute alloy components is guided by grand canonical density functional theory simulations using the calculated binding energies of the reaction intermediates CO*, CHO*, and OCCO* dimer as descriptors for the selectivity toward C2+ products. A physical vapor deposition catalyst testing platform is employed to isolate the effect of alloy composition on the C2+/C1 product branching ratio without interference from catalyst morphology or catalyst integration. Six dilute alloy catalysts are prepared and tested with respect to their C2+/C1 product ratio using different electrolyzer environments including selected tests in a 100-cm2 electrolyzer. Consistent with theory, CuAl, CuB, CuGa and especially CuSc show increased selectivity toward C2+ products by making CO dimerization energetically more favorable on the dominant Cu facets, demonstrating the power of using the dilute alloy approach to tune the selectivity of CO2 electrolysis.

2.
Nat Commun ; 15(1): 6105, 2024 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-39030209

RESUMO

Fish fecundity scales hyperallometrically with body mass, meaning larger females produce disproportionately more eggs than smaller ones. We explore this relationship beyond the species-level to estimate the "reproductive potential" of 1633 coral reef sites distributed globally. We find that, at the site-level, reproductive potential scales hyperallometrically with assemblage biomass, but with a smaller median exponent than at the species-level. Across all families, modelled reproductive potential is greater in fully protected sites versus fished sites. This difference is most pronounced for the important fisheries family, Serranidae. When comparing a scenario where 30% of sites are randomly fully protected to a current protection scenario, we estimate an increase in the reproductive potential of all families, and particularly for Serranidae. Such results point to the possible ecological benefits of the 30 × 30 global conservation target and showcase management options to promote the sustainability of population replenishment.


Assuntos
Recifes de Corais , Peixes , Reprodução , Animais , Peixes/fisiologia , Reprodução/fisiologia , Biomassa , Conservação dos Recursos Naturais , Feminino , Pesqueiros , Fertilidade/fisiologia , Ecossistema
3.
J Dermatol Sci ; 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-39043504

RESUMO

BACKGROUND: In tissue engineering, real-time monitoring of tumors and of the dynamics of the microenvironment within in vitro models has traditionally been hindered by the need to harvest the cultures to obtain material to analyze. Line-field confocal optical coherence tomography (LC-OCT) has proven to be useful in evaluating in vivo skin conditions, including melanoma, by capturing dynamic, three-dimensional (3D) information without the need for invasive procedures, such as biopsies. Additionally, the M-Duo Technology® developed by IMcoMET presents a unique opportunity for continuous in situ biomarker sampling, providing insights into local cellular behavior and interactions. OBJECTIVE: This study aimed to validate the non-destructive mapping capabilities of two advanced methodologies (LC-OCT by DAMAE Medical and M-Duo Technology® by IMcoMET) to investigate the living microenvironment of in vitro reconstructed human skin (RhS) and melanoma-RhS (Mel-RhS). METHODS: LC-OCT and M-Duo Technology® were compared to conventional analysis of the RhS and Mel-RhS microenvironments. RESULTS: LC-OCT successfully visualized the distinct layers of the epidermis and tumor structures within the Mel-RhS, identifying keratinocytes, melanocytes, tumor nests, and fibroblasts. The M-Duo Technology® revealed differences in in situ cytokine (IL-6) and chemokine (CCL2, CXCL10, and IL-8) secretion between Mel-RhS and the control RhS. Notably, such differences were not detected through conventional investigation of secreted proteins in culture supernatants. CONCLUSION: The combination of LC-OCT's high-resolution imaging and M-Duo Technology®'s in situ microenvironmental mapping has the potential to provide a synergistic platform for non-invasive, real-time analysis, allowing for prolonged observation of processes within Mel-RhS models without the need for culture disruption.

4.
Adv Mater ; : e2401534, 2024 May 25.
Artigo em Holandês | MEDLINE | ID: mdl-38795019

RESUMO

The exploration of 1D magnetism, frequently portrayed as spin chains, constitutes an actively pursued research field that illuminates fundamental principles in many-body problems and applications in magnonics and spintronics. The inherent reduction in dimensionality often leads to robust spin fluctuations, impacting magnetic ordering and resulting in novel magnetic phenomena. Here, structural, magnetic, and optical properties of highly anisotropic 2D van der Waals antiferromagnets that uniquely host spin chains are explored. First-principle calculations reveal that the weakest interaction is interchain, leading to essentially 1D magnetic behavior in each layer. With the additional degree of freedom arising from its anisotropic structure, the structure is engineered by alloying, varying the 1D spin chain lengths using electron beam irradiation, or twisting for localized patterning, and spin textures are calculated, predicting robust stability of the antiferromagnetic ordering. Comparing with other spin chain magnets, these materials are anticipated to bring fresh perspectives on harvesting low-dimensional magnetism.

5.
Inorg Chem ; 63(24): 10897-10914, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38795015

RESUMO

Contrast agents are important imaging probes in clinical MRI, allowing the identification of anatomic changes that otherwise would not be possible. Intensive research on the development of new contrast agents is being made to image specific pathological markers or sense local biochemical changes. The most widely used MRI contrast agents are based on gadolinium(III) complexes. Due to their very high charge density, they have low permeability through tight biological barriers such as the blood-brain barrier, hampering their application in the diagnosis of neurological disorders. In this study, we explore the interaction between the widely used contrast agent [Gd(DOTA)]- (Dotarem) and POPC lipid bilayers by means of molecular dynamics simulations. This metal complex is a standard reference where several chemical modifications have been introduced to improve key properties such as bioavailability and targeting. The simulations unveil detailed insights into the agent's interaction with the lipid bilayer, offering perspectives beyond experimental methods. Various properties, including the impact on global and local bilayer properties, were analyzed. As expected, the results indicate a low partition coefficient (KP) and high permeation barrier for this reference compound. Nevertheless, favorable interactions are established with the membrane leading to moderately long residence times. While coordination of one inner-sphere water molecule is maintained for the membrane-associated chelate, the physical-chemical attributes of [Gd(DOTA)]- as a MRI contrast agent are affected. Namely, increases in the rotational correlation times and in the residence time of the inner-sphere water are observed, with the former expected to significantly increase the water proton relaxivity. This work establishes a reference framework for the use of simulations to guide the rational design of new contrast agents with improved relaxivity and bioavailability and for the development of liposome-based formulations for use as imaging probes or theranostic agents.


Assuntos
Meios de Contraste , Bicamadas Lipídicas , Imageamento por Ressonância Magnética , Simulação de Dinâmica Molecular , Compostos Organometálicos , Meios de Contraste/química , Imageamento por Ressonância Magnética/métodos , Compostos Organometálicos/química , Compostos Organometálicos/síntese química , Bicamadas Lipídicas/química , Fosfatidilcolinas/química , Compostos Heterocíclicos
6.
Pest Manag Sci ; 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38801197

RESUMO

BACKGROUND: Chrysodeixis includens (Walker) and Rachiplusia nu (Guenée) are major Plusiinae pests of soybean in the Southern Cone region of South America. In recent decades, C. includens was the main defoliator of soybean in Brazil, but from 2021 onwards, R. nu emerged as an important soybean pest in various regions of the country. Here, we characterize the differential susceptibility and resistance to insecticides in these Plusiinae pests from two soybean regions of Brazil. RESULTS: Except for spinetoram and chlorfenapyr (comparable lethality against both species) and a Bt-based biopesticide (more lethal for C. includens), the tested insecticides showed higher lethality against R. nu than against C. includens, but populations of the same species, even separated by long distances, presented similar resistance levels. For both species, the 90% lethal concentration (LC90) values of most insecticides were higher than the field-recommended dose. Nevertheless, the field-recommended doses of spinetoram, metaflumizone, emamectin benzoate, cyclaniliprole and chlorfenapyr showed comparable control efficacy against both species, whereas indoxacarb, chlorantraniliprole, flubendiamide, teflubenzuron and chlorfluazuron were more lethal for R. nu, and methoxyfenozide and the Bt-based insecticide were more lethal for C. includens. Thiodicarb, methomyl and lambda-cyhalothrin showed low lethality against both species. CONCLUSIONS: Large interspecific differences in the susceptibility to insecticides was found in major Plusiinae pests of soybean in Brazil. Furthermore, variations in susceptibility to insecticides occurred consistently among species and populations, regardless of the collection site and thus despite unequal temporal and spatial exposure to insecticides. These results demonstrate that accurate species identification is essential for effective control of Plusiinae in soybean. © 2024 Society of Chemical Industry.

7.
ACS Nano ; 18(21): 13458-13467, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38739873

RESUMO

van der Waals (vdW) magnetic materials, such as Cr2Ge2Te6 (CGT), show promise for memory and logic applications. This is due to their broadly tunable magnetic properties and the presence of topological magnetic features such as skyrmionic bubbles. A systematic study of thickness and oxidation effects on magnetic domain structures is important for designing devices and vdW heterostructures for practical applications. Here, we investigate thickness effects on magnetic properties, magnetic domains, and bubbles in oxidation-controlled CGT crystals. We find that CGT exposed to ambient conditions for 5 days forms an oxide layer approximately 5 nm thick. This oxidation leads to a significant increase in the oxidation state of the Cr ions, indicating a change in local magnetic properties. This is supported by real-space magnetic texture imaging through Lorentz transmission electron microscopy. By comparing the thickness-dependent saturation field of oxidized and pristine crystals, we find that oxidation leads to a nonmagnetic surface layer that is thicker than the oxide layer alone. We also find that the stripe domain width and skyrmionic bubble size are strongly affected by the crystal thickness in pristine crystals. These findings underscore the impact of thickness and surface oxidation on the properties of CGT, such as saturation field and domain/skyrmionic bubble size, and suggest a pathway for manipulating magnetic properties through a controlled oxidation process.

8.
Cureus ; 16(2): e55260, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38558609

RESUMO

Lipedema, a chronic and painful disorder primarily affecting women without a definitive cure, has traditionally been managed with conservative therapy, notably complete decongestive therapy, across many countries. Recently, liposuction has been explored as a potential surgical treatment, prompting this study to evaluate its effectiveness as possibly the first-line therapy for lipedema. Through extensive literature searches in databases such as CrossRef, Web of Science, PubMed, and Google Scholar up to December 2023, and using the Newcastle-Ottawa Scale for quality assessment, the study selected seven studies for inclusion. Results showed significant post-operative improvements in spontaneous pain, edema, bruising, mobility, and quality of life among lipedema patients undergoing liposuction. However, over half of the patients still required conservative therapy after surgery. Despite these promising results, the study suggests caution due to lipedema's complexity, significant reliance on self-reported data, and limitations of the studies reviewed. Thus, while liposuction may offer symptomatic relief, it should be considered an adjunct, experimental therapy rather than a definitive cure, emphasizing the need for a comprehensive approach to care.

9.
Science ; 384(6693): 312-317, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38669572

RESUMO

Electrostatic capacitors are foundational components of advanced electronics and high-power electrical systems owing to their ultrafast charging-discharging capability. Ferroelectric materials offer high maximum polarization, but high remnant polarization has hindered their effective deployment in energy storage applications. Previous methodologies have encountered problems because of the deteriorated crystallinity of the ferroelectric materials. We introduce an approach to control the relaxation time using two-dimensional (2D) materials while minimizing energy loss by using 2D/3D/2D heterostructures and preserving the crystallinity of ferroelectric 3D materials. Using this approach, we were able to achieve an energy density of 191.7 joules per cubic centimeter with an efficiency greater than 90%. This precise control over relaxation time holds promise for a wide array of applications and has the potential to accelerate the development of highly efficient energy storage systems.

10.
Int J Obes (Lond) ; 48(7): 993-1002, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38538853

RESUMO

BACKGROUND: T-Lymphocyte activation is modulated by the adipokine leptin and serum concentrations of this hormone can be reduced with short-term calorie restriction. The aim of this study was to understand whether leptin per se is important in determining levels of T-lymphocyte activation in humans, by investigating whether the reduction in leptin concentration following calorie restriction is associated with a decrease in T-Lymphocyte activation in blood and adipose tissue. METHODS: Twelve men with overweight and obesity (age 35-55 years, waist circumference 95-115 cm) reduced their calorie intake by 50% for 3 consecutive days. Blood and subcutaneous adipose tissue were obtained for isolation of immune cells and cytokine analysis. CD4+ and CD8 + T-Lymphocytes were identified and characterised according to their expression of activation markers CD25 and CD69 by flow cytometry. RESULTS: Serum leptin was reduced by (mean ± SEM) 31 ± 16% (p < 0.001) following calorie restriction. The percentage of blood CD4 + CD25 + T-lymphocytes and level of CD25 expression on these lymphocytes were significantly reduced by 8 ± 10% (p = 0.016) and 8 ± 4% (p = 0.058), respectively. After calorie restriction, ex vivo leptin secretion from abdominal subcutaneous adipose tissue explants was not changed, and this corresponded with a lack of change in adipose tissue resident T-Lymphocyte activation. CONCLUSIONS: Serum leptin was reduced after calorie restriction and this was temporally associated with a reduction in activation of blood CD4 + CD25 + T-Lymphocytes. In abdominal subcutaneous adipose tissue, however, leptin secretion was unaltered, and there were no observed changes in adipose resident T-Lymphocyte activation.


Assuntos
Restrição Calórica , Leptina , Ativação Linfocitária , Obesidade , Sobrepeso , Humanos , Masculino , Leptina/sangue , Leptina/metabolismo , Adulto , Pessoa de Meia-Idade , Obesidade/sangue , Obesidade/imunologia , Obesidade/metabolismo , Sobrepeso/sangue , Sobrepeso/imunologia , Citometria de Fluxo , Tecido Adiposo/metabolismo , Tecido Adiposo/imunologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , Redução de Peso/fisiologia
11.
Int J Stroke ; : 17474930241246157, 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38546172

RESUMO

BACKGROUND AND OBJECTIVE: The Modified Rankin Scale (mRS) is a widely adopted scale for assessing stroke recovery. Despite limitations, the mRS has been adopted as primary outcome in most recent clinical acute stroke trials. Designed to be used by multidisciplinary clinical staff, the congruency of this scale is not consistent, which may lead to mistakes in clinical or research application. We aimed to develop and validate an interactive and automated digital tool for assessing the mRS-the iRankin. METHODS: A panel of five board-certified and mRS-trained vascular neurologists developed an automated flowchart based on current mRS literature. Two international experts were consulted on content and provided feedback on the prototype platform. The platform contained five vignettes and five real video cases, representing mRS grades 0-5. For validation, we invited neurological staff from six comprehensive stroke centers to complete an online assessment. Participants were randomized into two equal groups usual practice versus iRankin. The participants were randomly allocated in pairs for the congruency analysis. Weighted kappa (kw) and proportions were used to describe agreement. RESULTS: A total of 59 professionals completed the assessment. The kw was dramatically improved among nurses, 0.76 (95% confidence interval (CI) = 0.55-0.97) × 0.30 (0.07-0.67), and among vascular neurologists, 0.87 (0.72-1) × 0.82 (0.66-0.98). In the accuracy analysis, after the standard mRS values for the vignettes and videos were determined by a panel of experts, and considering each correct answer as equivalent to 1 point on a scale of 0-15, it revealed a higher mean of 10.6 (±2.2) in the iRankin group and 8.2 (±2.3) points in the control group (p = 0.02). In an adjusted analysis, the iRankin adoption was independently associated with the score of congruencies between reported and standard scores (beta coefficient = 2.22, 95% CI = 0.64-3.81, p = 0.007). CONCLUSION: The iRankin adoption led to a substantial or near-perfect agreement in all analyzed professional categories. More trials are needed to generalize our findings. Our user-friendly and free platform is available at https://www.irankinscale.com/.

12.
Nat Ecol Evol ; 8(4): 676-685, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38374185

RESUMO

Habitat associations underpin species ecologies in high-diversity systems. Within tropical, shallow water coral reefs, the relationship between fishes and corals is arguably the most iconic and highly scrutinized. A strong relationship between fishes and reef-building hard corals is often assumed, a belief supported by studies that document the decline of reef fishes following coral loss. However, the extent of this relationship is often unclear, as evidenced by conflicting reports. Here we assess the strength of this ecological association by relying on literature that has surveyed both fishes and corals synchronously. We quantitatively synthesize 723 bivariate correlation coefficients (from 66 papers), published over 38 years, that relate fish metrics (abundance, biomass and species richness) with the percentage of hard coral cover. Remarkably, despite extensive variation, the pattern of association on a global scale reveals a predominantly positive, albeit weak (|r| < 0.4), correlation. Even for commonly hypothesized drivers of fish-coral associations, fish family and trophic group, associations were consistently weak. These findings question our assumptions regarding the strength and ubiquity of fish-coral associations, and caution against assuming a direct and omnipresent relationship between these two iconic animal groups.


Assuntos
Antozoários , Animais , Recifes de Corais , Ecossistema , Biomassa , Peixes
13.
Int J Biol Macromol ; 263(Pt 1): 130292, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38382775

RESUMO

The insertion of hydrophobic and hydrophilic chains in the chitosan molecule can improve its antibacterial activity, expanding its range of application in several areas of medical-pharmaceutical sciences. Thus, this work aimed to increase the antibacterial activity of chitosan through the modification reaction with phthalic anhydride (QF) and subsequent reaction with ethylenediamine (QFE). The chitosan and derivatives obtained were characterized by elemental analysis, 13C Nuclear Magnetic Resonance (13C NMR), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TG), where it was possible to prove the chemical modification. Both materials showed a greater antibacterial inhibitory effect against Gram-positive bacteria, Staphylococcus aureus, emphasizing antibacterial activity against Gram-negative bacteria, Escherichia coli, with values above 70 % of the inhibitory effect, which is a promising result. Assays with human fibroblast cells by the [3-(4,5-dimethylthiazolyl)-2,5-diphenyl tetrazolium (MTT)] bromide reduction test did not indicate toxicity in the materials. Thus, the derived materials showed promise for biomedical applications since they combined excellent antibacterial activity against gram-positive and gram-negative strains and did not show cytotoxicity.


Assuntos
Quitosana , Humanos , Quitosana/química , Anidridos Ftálicos/farmacologia , Testes de Sensibilidade Microbiana , Antibacterianos/farmacologia , Antibacterianos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Escherichia coli , Etilenodiaminas/farmacologia , Difração de Raios X
14.
Inflammation ; 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38329636

RESUMO

Neutrophilic asthma is generally defined by poorly controlled symptoms and high levels of neutrophils in the lungs. Short-chain fatty acids (SCFAs) are proposed as nonpharmacological therapy for allergic asthma, but their impact on the neutrophilic asthma lacks evidence. SCFAs regulate immune cell responses and impact the inflammasome NLRP3, a potential pharmacological target for neutrophilic asthma. Here, we explored the capacity of SCFAs to mitigate murine-induced neutrophilic asthma and the contribution of NLRP3 to this asthma. The objective of this study is to analyze whether SCFAs can attenuate lung inflammation and tissue remodeling in murine neutrophilic asthma and NLRP3 contribution to this endotype. Wild-type (WT) C57BL6 mice orotracheally received 10 µg of HDM (house dust mite) in 80 µL of saline on days 0, 6-10. To explore SCFAs, each HDM group received 200 mM acetate, propionate, or butyrate. To explore NLRP3, Nlrp3 KO mice received the same protocol of HDM. On the 14th day, after euthanasia, bronchoalveolar lavage fluid (BALF) and lungs were collected to evaluate cellularity, inflammatory cytokines, and tissue remodeling. HDM group had increased BALF neutrophil influx, TNF-α, IFN-γ, IL-17A, collagen deposition, and mucus secretion compared to control. SCFAs distinctively attenuate lung inflammation. Only features of tissue remodeling were Nlrp3-dependent such as collagen deposition, mucus secretion, active TGF-ß cytokine, and IMs CD206+. SCFAs greatly decreased inflammatory cytokines and tissue remodeling. Only tissue remodeling was dependent on NLRP3. It reveals the potential of SCFAs to act as an additional therapy to mitigate neutrophilic asthma and the NLRP3 contribution to asthma.

15.
Phys Chem Chem Phys ; 26(10): 8469-8487, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38410922

RESUMO

Efficient surface passivation and toxic lead (Pb) are known obstacles to the photovoltaic application of perovskite-based solar cells. A possible solution for these problems is to use thin-films of two-dimensional (2D) perovskite-based materials and the replacement of Pb with alternative divalent cations (B); however, our atomistic understanding of the differences between (3D) three-dimensional and 2D perovskite-based materials is far from satisfactory. Herein, we report a systematic theoretical investigation based on ab initio density functional theory (DFT) calculations for both 3D MABX3 and the Ruddlesden-Popper 2D (BA)2(MA)B2X7 (B = Ge, Sn, Pb, and X = Cl, Br, I) compounds to investigate the differences (contrasts) in selected physical-chemical properties, i.e., structural parameters, energetic stability, electronic, and optical properties. We found an increased cation/anion charge separation because of the presence of organic spacers, which results in stronger Coulomb interactions in the inorganic framework, and hence, it enhances the cohesive energy (stability) within the inorganic layer. The inorganic layer constitutes the optically active region that contributes to the superior performance of perovskite-based solar cells. We quantified this effect by comparing the average electronic charges at the X sites in both 2D and 3D perovskites. This comparison is then correlated with variations in BX6-octahedron volumes, resulting in a monotonic relation. Moreover, the electronic structure characterization demonstrates that Ge-based systems present weakly sensitive band gaps to dimensionality due to a compensatory effect between Jahn-Teller distortions and quantum confinement. Lead-free GeI-, SnBr-, and SnI-based perovskites have DFT band gaps closer to the optimal value used in photovoltaic applications. Finally, as expected, the 2D systems absorption coefficients show pronounced anisotropy.

16.
Psychol Rep ; : 332941241227150, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38291607

RESUMO

In this paper, we conducted a meta-analytic review to examine the impact of social presence on individuals' performance on the Stroop task, shedding light on the cognitive processes underlying social facilitation. We followed PRISMA guidelines to identify and include 33 relevant studies in a multivariate random-effects meta-analysis. Our results show that social presence reliably modulates Stroop interference (a measure of cognitive control); specifically, participants exhibit lower Stroop interference when performing the task in the presence of others compared to performing it in isolation. We also found that the strength of the effect varies depending on the type of social presence: it is stronger with an attentive audience compared to an inattentive one, and null with an evaluative audience. Additionally, different features of the Stroop task itself moderate the effect; the effect is stronger for the classic version of the task compared to the semantic version, and for experiments that use mixed within-block trials compared to those with homogenous blocks. We also observed a negative relationship between the number of trials and the magnitude of the effect. Overall, these findings provide insights into the mechanisms by which the presence of others affects performance on the Stroop task, and how they align with social facilitation theories.

17.
ACS Nano ; 18(4): 3286-3294, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38227802

RESUMO

The controlled design of bimetallic nanoparticles (BNPs) is a key goal in tailoring their catalytic properties. Recently, biomimetic pathways demonstrated potent control over the distribution of different metals within BNPs, but a direct understanding of the peptide effect on the compositional distribution at the interparticle and intraparticle levels remains lacking. We synthesized two sets of PtAu systems with two peptides and correlated their structure, composition, and distributions with the catalytic activity. Structural and compositional analyses were performed by a combined machine learning-assisted refinement of X-ray absorption spectra and Z-contrast measurements by scanning transmission electron microscopy. The difference in the catalytic activities between nanoparticles synthesized with different peptides was attributed to the details of interparticle distribution of Pt and Au across these markedly heterogeneous systems, comprising Pt-rich, Au-rich, and Au core/Pt shell nanoparticles. The total amount of Pt in the shells of the BNPs was proposed to be the key catalytic activity descriptor. This approach can be extended to other systems of metals and peptides to facilitate the targeted design of catalysts with the desired activity.

18.
J Sleep Res ; : e14154, 2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38286415

RESUMO

Gender and age are well-established determinants of health and sleep health that influence overall health, which also often varies by gender and age. Sleep architecture is an important component of sleep health. The goal of this analysis was to examine whether associations between age and sleep stages differ by gender in the absence of moderate-severe obstructive sleep apnea (OSA) in a rural setting in Brazil. This study conducted polysomnography recordings in the Baependi Heart Study, a cohort of Brazilian adults. Our sample included 584 women and 309 men whose apnea-hypopnea index was ≤15 events/h. We used splines to distinguish non-linear associations between age, total sleep time, wake after sleep onset (WASO), N2, N3, and rapid-eye-movement sleep. The mean (standard deviation; range) age was 47 (14; 18-89) years. All sleep outcomes were associated with age. Compared to men, women had more N3 sleep and less WASO after adjusting for age. Model-based comparisons between genders at specific ages showed statistically higher mean WASO for men at ages 60 (+13.6 min) and 70 years (+19.5 min) and less N3 for men at ages 50 (-13.2 min), 60 (-19.0 min), and 70 years (-19.5 min) but no differences at 20, 30, 40 or 80 years. The other sleep measures did not differ by gender at any age. Thus, even in the absence of moderate-severe OSA, sleep architecture was associated with age across adulthood, and there were gender differences in WASO and N3 at older ages in this rural community.

19.
ACS Catal ; 14(1): 406-417, 2024 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-38205022

RESUMO

The oxygen species on Ag catalysts and reaction mechanisms for ethylene epoxidation and ethylene combustion continue to be debated in the literature despite decades of investigation. Fundamental details of ethylene oxidation by supported Ag/α-Al2O3 catalysts were revealed with the application of high-angle annular dark-field-scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy (HAADF-STEM-EDS), in situ techniques (Raman, UV-vis, X-ray diffraction (XRD), HS-LEIS), chemical probes (C2H4-TPSR and C2H4 + O2-TPSR), and steady-state ethylene oxidation and SSITKA (16O2 → 18O2 switch) studies. The Ag nanoparticles are found to carry a considerable amount of oxygen after the reaction. Density functional theory (DFT) calculations indicate the oxidative reconstructed p(4 × 4)-O-Ag(111) surface is stable relative to metallic Ag(111) under the relevant reaction environment. Multiple configurations of reactive oxygen species are present, and their relevant concentrations depend on treatment conditions. Selective ethylene oxidation to EO proceeds with surface Ag4-O2* species (dioxygen species occupying an oxygen site on a p(4 × 4)-O-Ag(111) surface) only present after strong oxidation of Ag. These experimental findings are strongly supported by the associated DFT calculations. Ethylene epoxidation proceeds via a Langmuir-Hinshelwood mechanism, and ethylene combustion proceeds via combined Langmuir-Hinshelwood (predominant) and Mars-van Krevelen (minor) mechanisms.

20.
Dalton Trans ; 53(2): 746-752, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38086661

RESUMO

The presented simulation protocol provides a solid foundation for exploring two-dimensional materials. Taking the TiBr2 2H monolayer as an example, this material displays promising TMDC-like optical and excitonic properties, making it an excellent candidate for optoelectronic and valleytronic applications. The direct band gap semiconductor (1.19 eV) is both structurally and thermodynamically stable, with spin-orbit coupling effects revealing a broken mirror symmetry in the K and K' valleys of the band structure, as confirmed by opposite values of the Berry curvature. A direct and bright exciton ground state was found, with an exciton binding energy of 0.56 eV. The study also revealed an optical helicity selection rule, suggesting selectivity in the valley excitation by specific circular light polarizations.

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